Like Canoe says, be careful of letting toddlers handle the chicks. They tend to squeeze objects and that will damage a chick's delicate body. Other than that, handling chicks gently is not harmful and they can survive just fine out of the brooder for a few minutes.
Remember, the heat guidelines are just that. Use them to calibrate the heat lamp, having the temp directly beneath around 90-95. There should be plenty of space for the chicks to cool down. People make the mistake of thinking chicks are like hamburger patties that need to be kept hot. They are more like lizards that warm up in the sun and then scurry on about their business. They are simply regulating their temperature using the heat lamp to do it. Overheating is far more dangerous than keeping the brooder on the cool side.
Watch the chicks. They will be scattered around the brooder if it's just right. If they aren't warm enough they will be crowded together in a pile directly beneath the lamp. That's your signal to lower the lamp so they get a bit more warmth.